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ack/lang/cem/cemcom/eval.c
ceriel 09125cce6b redesign of ival, other minor changes
1987-03-25 23:14:43 +00:00

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/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/* EXPRESSION-CODE GENERATOR */
#include "nofloat.h"
#include <em.h>
#include "debug.h"
#include "nobitfield.h"
#include "dataflow.h"
#include "arith.h"
#include "type.h"
#include "idf.h"
#include "label.h"
#include "code.h"
#include "assert.h"
#include "def.h"
#include "expr.h"
#include "sizes.h"
#include "Lpars.h"
#include "level.h"
#include "stack.h"
#include "align.h"
#include "mes.h"
#include "atw.h"
#define CRASH() crash("EVAL: CRASH at line %u", __LINE__)
#define toword(n) ((n) < word_size ? word_size : (n))
char *symbol2str();
char *long2str();
arith tmp_pointer_var();
/* EVAL() is the main expression-tree evaluator, which turns
any legal expression tree into EM code. Parameters:
struct expr *expr
pointer to root of the expression tree to be evaluated
int val
indicates whether the resulting expression is to be
dereferenced (if val == RVAL and expr->ex_lvalue == 1)
or not (val == LVAL). The latter case indicates that
the resulting expression is an lvalue expression which
should not be dereferenced by EVAL
int code
indicates whether the expression tree must be turned
into EM code or not. E.g. the expression statement "12;"
delivers the expression "12" to EVAL while this should
not result in any EM code
label false_label, label true_label
if the expression is a logical or relational expression
and if the loop of the program depends on the resulting
value then EVAL generates jumps to the specified program
labels, in case they are specified (i.e. are non-zero)
*/
EVAL(expr, val, code, true_label, false_label)
register struct expr *expr;
int val, code;
label true_label, false_label;
{
register int gencode = (code == TRUE);
switch (expr->ex_class) {
case Value: /* just a simple value */
if (gencode)
load_val(expr, val);
break;
case String: /* a string constant */
if (gencode) {
string2pointer(expr);
C_lae_dlb(expr->VL_LBL, expr->VL_VALUE);
}
break;
#ifndef NOFLOAT
case Float: /* a floating constant */
if (gencode) {
label datlab = data_label();
C_df_dlb(datlab);
C_rom_fcon(expr->FL_VALUE, expr->ex_type->tp_size);
C_lae_dlb(datlab, (arith)0);
C_loi(expr->ex_type->tp_size);
}
break;
#endif NOFLOAT
case Oper: /* compound expression */
{
int oper = expr->OP_OPER;
register struct expr *left = expr->OP_LEFT;
register struct expr *right = expr->OP_RIGHT;
register struct type *tp = expr->OP_TYPE;
if (tp->tp_fund == ERRONEOUS || (expr->ex_flags & EX_ERROR)) {
/* stop immediately */
break;
}
if (tp->tp_fund == VOID)
gencode = 0;
switch (oper) {
case '+':
/* We have the following possibilities :
int + int, pointer + int, pointer + long,
long + long, double + double
*/
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode) {
switch (tp->tp_fund) {
case INT:
case LONG:
if (tp->tp_unsigned)
C_adu(tp->tp_size);
else
C_adi(tp->tp_size);
break;
case POINTER:
C_ads(right->ex_type->tp_size);
break;
#ifndef NOFLOAT
case DOUBLE:
C_adf(tp->tp_size);
break;
#endif NOFLOAT
default:
crash("bad type +");
}
}
break;
case '-':
if (left == 0) { /* unary */
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode) {
switch (tp->tp_fund) {
case INT:
case LONG:
case POINTER:
C_ngi(tp->tp_size);
break;
#ifndef NOFLOAT
case DOUBLE:
C_ngf(tp->tp_size);
break;
#endif NOFLOAT
default:
CRASH();
}
}
break;
}
/* else binary; we have the following flavours:
int - int, pointer - int, pointer - long,
pointer - pointer, long - long, double - double
*/
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (!gencode)
break;
switch (tp->tp_fund) {
case INT:
case LONG:
if (tp->tp_unsigned)
C_sbu(tp->tp_size);
else
C_sbi(tp->tp_size);
break;
case POINTER:
if (right->ex_type->tp_fund == POINTER)
C_sbs(pointer_size);
else {
C_ngi(right->ex_type->tp_size);
C_ads(right->ex_type->tp_size);
}
break;
#ifndef NOFLOAT
case DOUBLE:
C_sbf(tp->tp_size);
break;
#endif NOFLOAT
default:
crash("bad type -");
}
break;
case '*':
if (left == 0) /* unary */
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
else { /* binary */
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
switch (tp->tp_fund) {
case INT:
case LONG:
case POINTER:
if (tp->tp_unsigned)
C_mlu(tp->tp_size);
else
C_mli(tp->tp_size);
break;
#ifndef NOFLOAT
case DOUBLE:
C_mlf(double_size);
break;
#endif NOFLOAT
default:
crash("bad type *");
}
}
break;
case '/':
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
switch (tp->tp_fund) {
case INT:
case LONG:
case POINTER:
if (tp->tp_unsigned)
C_dvu(tp->tp_size);
else
C_dvi(tp->tp_size);
break;
#ifndef NOFLOAT
case DOUBLE:
C_dvf(double_size);
break;
#endif NOFLOAT
default:
crash("bad type /");
}
break;
case '%':
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
ASSERT(tp->tp_fund==INT || tp->tp_fund==LONG);
if (gencode)
if (tp->tp_unsigned)
C_rmu(tp->tp_size);
else
C_rmi(tp->tp_size);
break;
case LEFT:
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
if (tp->tp_unsigned)
C_slu(tp->tp_size);
else
C_sli(tp->tp_size);
break;
case RIGHT:
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
if (tp->tp_unsigned)
C_sru(tp->tp_size);
else
C_sri(tp->tp_size);
break;
case '<':
case LESSEQ:
case '>':
case GREATEREQ:
case EQUAL:
case NOTEQUAL:
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode) {
/* The operands have the same type */
arith size = left->ex_type->tp_size;
switch (tp->tp_fund) {
case INT:
case LONG:
if (left->ex_type->tp_unsigned)
C_cmu(size);
else
C_cmi(size);
break;
#ifndef NOFLOAT
case FLOAT: /* thought they were converted??? */
case DOUBLE:
C_cmf(size);
break;
#endif NOFLOAT
case POINTER:
C_cmp();
break;
case ENUM:
C_cmi(size);
break;
default:
CRASH();
}
if (true_label != 0) {
compare(oper, true_label);
C_bra(false_label);
}
else {
truthvalue(oper);
}
}
break;
case '&':
case '|':
case '^':
/* both operands should have type int */
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode) {
arith size = tp->tp_size;
if (size < word_size)
size = word_size;
switch (oper) {
case '&':
C_and(size);
break;
case '|':
C_ior(size);
break;
case '^':
C_xor(size);
break;
}
}
break;
case '=': {
int newcode = tp->tp_size > 0; /* CJ */
#ifndef NOBITFIELD
if (left->ex_type->tp_fund == FIELD) {
eval_field(expr, gencode);
break;
}
#endif NOBITFIELD
EVAL(right, RVAL, newcode, NO_LABEL, NO_LABEL);
if (gencode)
C_dup(ATW(tp->tp_size));
if (left->ex_class != Value) {
EVAL(left, LVAL, newcode, NO_LABEL, NO_LABEL);
if (newcode)
store_block(tp->tp_size, tp->tp_align);
}
else if (newcode)
store_val(&(left->ex_object.ex_value),
left->ex_type);
}
break;
case PLUSAB:
case MINAB:
case TIMESAB:
case DIVAB:
case MODAB:
case LEFTAB:
case RIGHTAB:
case ANDAB:
case XORAB:
case ORAB:
case POSTINCR:
case POSTDECR:
case PLUSPLUS:
case MINMIN:
{
arith old_offset, tmp;
int compl; /* Complexity of left operand */
int newcode = left->ex_type->tp_size > 0; /* CJ */
#ifndef NOBITFIELD
if (left->ex_type->tp_fund == FIELD) {
eval_field(expr, gencode);
break;
}
#endif NOBITFIELD
if (newcode && left->ex_class == Value) {
compl = 0; /* Value */
load_val(left, RVAL);
}
else
if (left->ex_depth == 1 &&
!(left->ex_flags & EX_SIDEEFFECTS)) {
compl = 1;
EVAL(left, RVAL, newcode, NO_LABEL, NO_LABEL);
}
else {
compl = 2; /* otherwise */
EVAL(left, LVAL, newcode, NO_LABEL, NO_LABEL);
if (newcode) {
tmp = tmp_pointer_var(&old_offset);
C_dup(pointer_size);
C_lal(tmp);
C_sti(pointer_size);
C_loi(left->ex_type->tp_size);
}
}
if (newcode) {
if (gencode && (oper == POSTINCR ||
oper == POSTDECR))
C_dup(ATW(left->ex_type->tp_size));
conversion(left->ex_type, tp);
}
EVAL(right, RVAL, newcode, NO_LABEL, NO_LABEL);
if (newcode) {
int dupval = gencode && oper != POSTINCR &&
oper != POSTDECR;
assop(tp, oper);
conversion(tp, left->ex_type);
if (compl == 0) {
store_val(&(left->ex_object.ex_value),
left->ex_type);
if (dupval) load_val(left, RVAL);
}
else if (compl == 1) {
EVAL(left, LVAL,1, NO_LABEL, NO_LABEL);
C_sti(left->ex_type->tp_size);
if (dupval) {
EVAL(left, LVAL, 1, NO_LABEL,
NO_LABEL);
C_loi(left->ex_type->tp_size);
}
}
else {
C_lal(tmp); /* always init'd */
C_loi(pointer_size);
C_sti(left->ex_type->tp_size);
if (dupval) {
C_lal(tmp);
C_loi(pointer_size);
C_loi(left->ex_type->tp_size);
}
free_tmp_var(old_offset);
}
}
break;
}
case '(':
{
register struct expr *ex;
arith ParSize = (arith)0;
if ((ex = right) != NILEXPR) {
/* function call with parameters*/
while ( ex->ex_class == Oper &&
ex->OP_OPER == PARCOMMA
) {
EVAL(ex->OP_RIGHT, RVAL,
ex->ex_type->tp_size > 0,
NO_LABEL, NO_LABEL);
ParSize += ATW(ex->ex_type->tp_size);
ex = ex->OP_LEFT;
}
EVAL(ex, RVAL, ex->ex_type->tp_size > 0,
NO_LABEL, NO_LABEL);
ParSize += ATW(ex->ex_type->tp_size);
}
if (left->ex_class == Value && left->VL_CLASS == Name) {
/* e.g., main() { (*((int (*)())0))(); } */
C_cal(left->VL_IDF->id_text);
#ifdef DATAFLOW
{ extern char options[];
if (options['d'])
DfaCallFunction(
left->VL_IDF->id_text);
}
#endif DATAFLOW
}
else {
EVAL(left, LVAL, TRUE, NO_LABEL, NO_LABEL);
C_cai();
}
/* remove parameters from stack */
if (ParSize > (arith)0)
C_asp(ParSize);
if (gencode) {
if (is_struct_or_union(tp->tp_fund)) {
C_lfr(pointer_size);
load_block(tp->tp_size, tp->tp_align);
}
else
C_lfr(ATW(tp->tp_size));
}
break;
}
case '.':
EVAL(left, LVAL, gencode, NO_LABEL, NO_LABEL);
ASSERT(is_cp_cst(right));
if (gencode)
C_adp(right->VL_VALUE);
break;
case ARROW:
EVAL(left, RVAL, gencode, NO_LABEL, NO_LABEL);
ASSERT(is_cp_cst(right));
if (gencode)
C_adp(right->VL_VALUE);
break;
case ',':
EVAL(left, RVAL, FALSE, NO_LABEL, NO_LABEL);
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
break;
case '~':
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
C_com(tp->tp_size);
break;
case '?': /* must be followed by ':' */
{
label l_true = text_label();
label l_false = text_label();
label l_end = text_label();
EVAL(left, RVAL, TRUE, l_true, l_false);
C_df_ilb(l_true);
EVAL(right->OP_LEFT, RVAL, gencode, NO_LABEL, NO_LABEL);
C_bra(l_end);
C_df_ilb(l_false);
EVAL(right->OP_RIGHT, RVAL, gencode, NO_LABEL, NO_LABEL);
C_df_ilb(l_end);
break;
}
case OR:
case AND: {
label l_false, l_true, l_maybe;
l_maybe = text_label();
if (true_label) {
l_false = false_label;
l_true = true_label;
}
else {
l_false = text_label();
l_true = gencode ? text_label(): l_false;
}
EVAL(left, RVAL, TRUE, oper == AND ? l_maybe : l_true,
oper == AND ? l_false : l_maybe);
C_df_ilb(l_maybe);
EVAL(right, RVAL, gencode, l_true, l_false);
if (gencode && !true_label) {
label l_end = text_label();
C_df_ilb(l_true);
C_loc((arith)1);
C_bra(l_end);
C_df_ilb(l_false);
C_loc((arith)0);
C_df_ilb(l_end);
}
else {
if (! true_label) C_df_ilb(l_false);
}
}
break;
case '!':
if (true_label == 0) {
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode) {
C_teq();
}
}
else
EVAL(right, RVAL, gencode, false_label,
true_label);
break;
case INT2INT:
#ifndef NOFLOAT
case INT2FLOAT:
case FLOAT2INT:
case FLOAT2FLOAT:
#endif NOFLOAT
EVAL(right, RVAL, gencode, NO_LABEL, NO_LABEL);
if (gencode)
conversion(right->ex_type, left->ex_type);
break;
default:
crash("(EVAL) bad operator %s\n", symbol2str(oper));
}
/* If the rvalue of the expression is required but
only its lvalue is evaluated, its rvalue is
loaded by the following statements:
*/
if (gencode && val == RVAL && expr->ex_lvalue == 1)
load_block(expr->ex_type->tp_size,
expr->ex_type->tp_align);
break;
}
default:
crash("(EVAL) bad expression class");
}
}
/* compare() serves as an auxiliary function of EVAL */
compare(relop, lbl)
int relop;
label lbl;
{
switch (relop) {
case '<':
C_zlt(lbl);
break;
case LESSEQ:
C_zle(lbl);
break;
case '>':
C_zgt(lbl);
break;
case GREATEREQ:
C_zge(lbl);
break;
case EQUAL:
C_zeq(lbl);
break;
case NOTEQUAL:
C_zne(lbl);
break;
default:
CRASH();
}
}
/* truthvalue() serves as an auxiliary function of EVAL */
truthvalue(relop)
int relop;
{
switch (relop) {
case '<':
C_tlt();
break;
case LESSEQ:
C_tle();
break;
case '>':
C_tgt();
break;
case GREATEREQ:
C_tge();
break;
case EQUAL:
C_teq();
break;
case NOTEQUAL:
C_tne();
break;
default:
CRASH();
}
}
/* assop() generates the opcode of an assignment operators op= */
assop(type, oper)
register struct type *type;
int oper;
{
register arith size;
register uns = type->tp_unsigned;
if ((size = type->tp_size) < word_size)
size = word_size;
switch (type->tp_fund) {
case CHAR:
case SHORT:
case INT:
case LONG:
case ENUM:
switch (oper) {
case PLUSAB:
case PLUSPLUS:
case POSTINCR:
if (uns)
C_adu(size);
else
C_adi(size);
break;
case MINAB:
case MINMIN:
case POSTDECR:
if (uns)
C_sbu(size);
else
C_sbi(size);
break;
case TIMESAB:
if (uns)
C_mlu(size);
else
C_mli(size);
break;
case DIVAB:
if (uns)
C_dvu(size);
else
C_dvi(size);
break;
case MODAB:
if (uns)
C_rmu(size);
else
C_rmi(size);
break;
case LEFTAB:
if (uns)
C_slu(size);
else
C_sli(size);
break;
case RIGHTAB:
if (uns)
C_sru(size);
else
C_sri(size);
break;
case ANDAB:
C_and(size);
break;
case XORAB:
C_xor(size);
break;
case ORAB:
C_ior(size);
break;
}
break;
#ifndef NOFLOAT
case FLOAT:
case DOUBLE:
switch (oper) {
case PLUSAB:
case PLUSPLUS:
case POSTINCR:
C_adf(size);
break;
case MINAB:
case MINMIN:
case POSTDECR:
C_sbf(size);
break;
case TIMESAB:
C_mlf(size);
break;
case DIVAB:
C_dvf(size);
break;
}
break;
#endif NOFLOAT
case POINTER:
if (oper == MINAB || oper == MINMIN || oper == POSTDECR)
C_ngi(size);
C_ads(size);
break;
case ERRONEOUS:
break;
default:
crash("(assop) bad type %s\n", symbol2str(type->tp_fund));
}
}
/* tmp_pointer_var() returns the EM address of a new temporary
pointer variable needed at increment, decrement and assignment
operations to store the address of some variable or lvalue-expression.
*/
arith
tmp_pointer_var(oldoffset)
arith *oldoffset; /* previous allocated address */
{
register struct stack_level *stl = local_level;
*oldoffset = stl->sl_local_offset;
stl->sl_local_offset =
- align(-stl->sl_local_offset + pointer_size, pointer_align);
if (stl->sl_local_offset < stl->sl_max_block)
stl->sl_max_block = stl->sl_local_offset;
return stl->sl_local_offset;
}
/* free_tmp_var() returns the address allocated by tmp_pointer_var()
and resets the last allocated address.
*/
free_tmp_var(oldoffset)
arith oldoffset;
{
local_level->sl_local_offset = oldoffset;
}
/* store_val() generates code for a store operation.
There are four ways of storing data:
- into a global variable
- into an automatic local variable
- into a local static variable
- absolute addressing
*/
store_val(vl, tp)
register struct value *vl;
struct type *tp;
{
arith size = tp->tp_size;
int tpalign = tp->tp_align;
int al_on_word;
register int inword;
register int indword;
arith val = vl->vl_value;
if (vl->vl_class == Const) { /* absolute addressing */
load_cst(val, pointer_size);
store_block(size, tpalign);
return;
}
al_on_word = (tpalign % word_align == 0);
if (!(inword = (size == word_size && al_on_word)))
indword = (size == dword_size && al_on_word);
if (vl->vl_class == Name) {
register struct idf *id = vl->vl_data.vl_idf;
register struct def *df = id->id_def;
if (df->df_level == L_GLOBAL) {
if (inword)
C_ste_dnam(id->id_text, val);
else
if (indword)
C_sde_dnam(id->id_text, val);
else {
C_lae_dnam(id->id_text, val);
store_block(size, tpalign);
}
}
else {
ASSERT(df->df_sc != STATIC);
if (inword)
C_stl(df->df_address + val);
else
if (indword)
C_sdl(df->df_address + val);
else {
C_lal(df->df_address + val);
store_block(size, tpalign);
df->df_register = REG_NONE;
}
}
}
else {
label dlb = vl->vl_data.vl_lbl;
ASSERT(vl->vl_class == Label);
if (inword)
C_ste_dlb(dlb, val);
else
if (indword)
C_sde_dlb(dlb, val);
else {
C_lae_dlb(dlb, val);
store_block(size, tpalign);
}
}
}
/* load_val() generates code for stacking a certain value (from ex),
which can be obtained in one of the following ways:
- value from absolute addressed memory
- constant value
- function result
- global variable
- static variable
- local variable
*/
load_val(expr, rlval)
register struct expr *expr; /* expression containing the value */
int rlval; /* generate either LVAL or RVAL */
{
register struct type *tp = expr->ex_type;
int rvalue = (rlval == RVAL && expr->ex_lvalue != 0);
arith size = tp->tp_size;
int tpalign = tp->tp_align;
int al_on_word;
register int inword, indword;
register arith val = expr->VL_VALUE;
if (expr->VL_CLASS == Const) {
if (rvalue) { /* absolute addressing */
load_cst(val, pointer_size);
load_block(size, tpalign);
}
else /* integer, unsigned, long, enum etc */
load_cst(val, size);
return;
}
if (rvalue) {
al_on_word = (tpalign % word_align == 0);
if (!(inword = (size == word_size && al_on_word)))
indword = (size == dword_size && al_on_word);
}
if (expr->VL_CLASS == Label) {
if (rvalue) {
if (inword)
C_loe_dlb(expr->VL_LBL, val);
else
if (indword)
C_lde_dlb(expr->VL_LBL, val);
else {
C_lae_dlb(expr->VL_LBL, val);
load_block(size, tpalign);
}
}
else {
C_lae_dlb(expr->VL_LBL, (arith)0);
C_adp(val);
}
}
else {
register struct idf *id = expr->VL_IDF;
register struct def *df;
ASSERT(expr->VL_CLASS == Name);
if ((df = id->id_def)->df_type->tp_fund == FUNCTION)
/* the previous statement tried to catch a function
identifier, which may be cast to a pointer to a
function.
ASSERT(!(rvalue)); ???
*/
C_lpi(id->id_text);
else
if (df->df_level == L_GLOBAL) {
if (rvalue) {
if (inword)
C_loe_dnam(id->id_text, val);
else
if (indword)
C_lde_dnam(id->id_text, val);
else {
C_lae_dnam(id->id_text, val);
load_block(size, tpalign);
}
}
else {
C_lae_dnam(id->id_text, (arith)0);
C_adp(val);
}
}
else {
ASSERT(df->df_sc != STATIC);
if (rvalue) {
if (inword)
C_lol(df->df_address + val);
else
if (indword)
C_ldl(df->df_address + val);
else {
C_lal(df->df_address + val);
load_block(size, tpalign);
df->df_register = REG_NONE;
}
}
else {
C_lal(df->df_address);
C_adp(val);
df->df_register = REG_NONE;
}
}
}
}
load_cst(val, siz)
arith val, siz;
{
if (siz <= word_size)
C_loc(val);
else
if (siz == dword_size)
C_ldc(val);
else {
label datlab;
C_df_dlb(datlab = data_label());
C_rom_icon(long2str((long)val, 10), siz);
C_lae_dlb(datlab, (arith)0);
C_loi(siz);
}
}
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